[ViewVC] Diff of: cvs/gvpe/src/vpn

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs.
Revision 1.49 by root, Tue Feb 8 23:11:36 2011 UTC

…		…
1	/*	1	/*
2	vpn_dns.C -- handle the dns tunnel part of the protocol.	2	vpn_dns.C -- handle the dns tunnel part of the protocol.
3	Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de>	3	Copyright (C) 2003-2008 Marc Lehmann <gvpe@schmorp.de>
4		4
5	This file is part of GVPE.	5	This file is part of GVPE.
6		6
7	GVPE is free software; you can redistribute it and/or modify	7	GVPE is free software; you can redistribute it and/or modify it
8	it under the terms of the GNU General Public License as published by	8	under the terms of the GNU General Public License as published by the
9	the Free Software Foundation; either version 2 of the License, or	9	Free Software Foundation; either version 3 of the License, or (at your
10	(at your option) any later version.	10	option) any later version.
11		11
12	This program is distributed in the hope that it will be useful,	12	This program is distributed in the hope that it will be useful, but
13	but WITHOUT ANY WARRANTY; without even the implied warranty of	13	WITHOUT ANY WARRANTY; without even the implied warranty of
14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15	GNU General Public License for more details.	15	Public License for more details.
16		16
17	You should have received a copy of the GNU General Public License	17	You should have received a copy of the GNU General Public License along
18	along with gvpe; if not, write to the Free Software	18	with this program; if not, see <http://www.gnu.org/licenses/>.
19	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA	19
		20	Additional permission under GNU GPL version 3 section 7
		21
		22	If you modify this Program, or any covered work, by linking or
		23	combining it with the OpenSSL project's OpenSSL library (or a modified
		24	version of that library), containing parts covered by the terms of the
		25	OpenSSL or SSLeay licenses, the licensors of this Program grant you
		26	additional permission to convey the resulting work. Corresponding
		27	Source for a non-source form of such a combination shall include the
		28	source code for the parts of OpenSSL used as well as that of the
		29	covered work.
20	*/	30	*/
		31
		32	// TODO: EDNS0 option to increase dns mtu?
		33	// TODO: re-write dns packet parsing/creation using a safe mem-buffer
		34	// to ensure no buffer overflows or similar problems.
21		35
22	#include "config.h"	36	#include "config.h"
23		37
24	#if ENABLE_DNS	38	#if ENABLE_DNS
25		39
26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.	40	// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27	// it's a hack, use only in emergency situations please.	41	// it's a hack, use only in emergency situations please.
28		42
29	#include <cstring>	43	#include <cstring>
		44	#include <cassert>
30		45
31	#include <sys/types.h>	46	#include <sys/types.h>
32	#include <sys/socket.h>	47	#include <sys/socket.h>
33	#include <sys/wait.h>	48	#include <sys/wait.h>
34	#include <sys/uio.h>	49	#include <sys/uio.h>
37	#include <unistd.h>	52	#include <unistd.h>
38	#include <fcntl.h>	53	#include <fcntl.h>
39		54
40	#include <map>	55	#include <map>
41		56
		57	#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
42	#include <gmp.h>	58	#include <gmp.h>
43		59
44	#include "netcompat.h"	60	#include "netcompat.h"
45		61
46	#include "vpn.h"	62	#include "vpn.h"
47		63
48	#define MIN_RETRY 1.	64	#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
49	#define MAX_RETRY 6.	65	#define ACTIVITY_INTERVAL 5.
50		66
51	#define MAX_OUTSTANDING 400 // max. outstanding requests	67	#define INITIAL_TIMEOUT 0.1 // retry timeouts
		68	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
		69
		70	#define MAX_SEND_INTERVAL 2. // optimistic?
		71
52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	72	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
53	#define MAX_RATE 100 // requests/s
54	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE	73	#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
55		74
56	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	75	#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well
57	// 240 leaves about 4 bytes of server reply data	76	// 240 leaves about 4 bytes of server reply data
58	// every two request byte sless give room for one reply byte	77	// every request byte less give room for two reply bytes
59		78
60	#define SEQNO_MASK 0xffff	79	#define SEQNO_MASK 0x3fff
61	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	80	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
62		81
63	#define MAX_LBL_SIZE 63	82	#define MAX_LBL_SIZE 63
64	#define MAX_PKT_SIZE 512	83	#define MAX_PKT_SIZE 512
65		84
		85	#define RR_TYPE_A 1
		86	#define RR_TYPE_NULL 10
66	#define RR_TYPE_TXT 16	87	#define RR_TYPE_TXT 16
		88	#define RR_TYPE_AAAA 28
67	#define RR_TYPE_ANY 255	89	#define RR_TYPE_ANY 255
		90
68	#define RR_CLASS_IN 1	91	#define RR_CLASS_IN 1
		92
		93	#define CMD_IP_1 207
		94	#define CMD_IP_2 46
		95	#define CMD_IP_3 236
		96	#define CMD_IP_RST 29
		97	#define CMD_IP_SYN 113
		98	#define CMD_IP_REJ 32
69		99
70	// works for cmaps up to 255 (not 256!)	100	// works for cmaps up to 255 (not 256!)
71	struct charmap	101	struct charmap
72	{	102	{
73	enum { INVALID = (u8)255 };	103	enum { INVALID = (u8)255 };
…		…
138	enc_len [len] = n;	168	enc_len [len] = n;
139	dec_len [n] = len;	169	dec_len [n] = len;
140	}	170	}
141	}	171	}
142		172
		173	unsigned int
143	unsigned int basecoder::encode_len (unsigned int len)	174	basecoder::encode_len (unsigned int len)
144	{	175	{
145	return enc_len [len];	176	return enc_len [len];
146	}	177	}
147		178
		179	unsigned int
148	unsigned int basecoder::decode_len (unsigned int len)	180	basecoder::decode_len (unsigned int len)
149	{	181	{
150	while (len && !dec_len [len])	182	while (len && !dec_len [len])
151	--len;	183	--len;
152		184
153	return dec_len [len];	185	return dec_len [len];
154	}	186	}
155		187
		188	unsigned int
156	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)	189	basecoder::encode (char dst, u8 src, unsigned int len)
157	{	190	{
158	if (!len)	191	if (!len \|\| len > MAX_DEC_LEN)
159	return 0;	192	return 0;
160		193
161	int elen = encode_len (len);	194	int elen = encode_len (len);
162		195
163	mp_limb_t m [MAX_LIMBS];	196	mp_limb_t m [MAX_LIMBS];
…		…
180	*dst++ = cmap.encode [dst_ [i]];	213	*dst++ = cmap.encode [dst_ [i]];
181		214
182	return elen;	215	return elen;
183	}	216	}
184		217
		218	unsigned int
185	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)	219	basecoder::decode (u8 dst, char src, unsigned int len)
186	{	220	{
187	if (!len)	221	if (!len \|\| len > MAX_ENC_LEN)
188	return 0;	222	return 0;
189		223
190	u8 src_ [MAX_ENC_LEN];	224	u8 src_ [MAX_ENC_LEN];
191	unsigned int elen = 0;	225	unsigned int elen = 0;
192		226
…		…
239	}	273	}
240	abort ();	274	abort ();
241	}	275	}
242	#endif	276	#endif
243		277
244	// the following sequence has been crafted to	278	//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
245	// a) look somewhat random
246	// b) the even (and odd) indices never share the same character as upper/lowercase
247	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)
248	// the other sequences are obviously derived
249	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	279	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
250	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	280	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet	281	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
252	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	282	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
253		283
254	/////////////////////////////////////////////////////////////////////////////	284	/////////////////////////////////////////////////////////////////////////////
255		285
256	#define HDRSIZE 6	286	#define HDRSIZE 6
257		287
		288	inline void
258	inline void encode_header (char *data, int clientid, int seqno)	289	encode_header (char *data, int clientid, int seqno, int retry = 0)
259	{	290	{
260	u8 hdr[3] = { clientid, seqno >> 8, seqno };	291	seqno &= SEQNO_MASK;
		292
		293	u8 hdr[3] = {
		294	clientid,
		295	(seqno >> 8) \| (retry << 6),
		296	seqno,
		297	};
261		298
262	assert (clientid < 256);	299	assert (clientid < 256);
263		300
264	cdc26.encode (data, hdr, 3);	301	cdc26.encode (data, hdr, 3);
265	}	302	}
266		303
		304	inline void
267	inline void decode_header (char *data, int &clientid, int &seqno)	305	decode_header (char *data, int &clientid, int &seqno)
268	{	306	{
269	u8 hdr[3];	307	u8 hdr[3];
270		308
271	cdc26.decode (hdr, data, HDRSIZE);	309	cdc26.decode (hdr, data, HDRSIZE);
272		310
273	clientid = hdr[0];	311	clientid = hdr[0];
274	seqno = (hdr[1] << 8) \| hdr[2];	312	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
275	}	313	}
276		314
277	/////////////////////////////////////////////////////////////////////////////	315	/////////////////////////////////////////////////////////////////////////////
278		316
279	struct byte_stream	317	struct byte_stream
…		…
305	byte_stream::~byte_stream ()	343	byte_stream::~byte_stream ()
306	{	344	{
307	delete data;	345	delete data;
308	}	346	}
309		347
		348	void
310	void byte_stream::remove (int count)	349	byte_stream::remove (int count)
311	{	350	{
312	if (count > fill)	351	if (count > fill)
313	abort ();	352	assert (count <= fill);
314		353
315	memmove (data, data + count, fill -= count);	354	memmove (data, data + count, fill -= count);
316	}	355	}
317		356
		357	bool
318	bool byte_stream::put (u8 *data, unsigned int datalen)	358	byte_stream::put (u8 *data, unsigned int datalen)
319	{	359	{
320	if (maxsize - fill < datalen)	360	if (maxsize - fill < datalen)
321	return false;	361	return false;
322		362
323	memcpy (this->data + fill, data, datalen); fill += datalen;	363	memcpy (this->data + fill, data, datalen); fill += datalen;
324		364
325	return true;	365	return true;
326	}	366	}
327		367
		368	bool
328	bool byte_stream::put (vpn_packet *pkt)	369	byte_stream::put (vpn_packet *pkt)
329	{	370	{
330	if (maxsize - fill < pkt->len + 2)	371	if (maxsize - fill < pkt->len + 2)
331	return false;	372	return false;
332		373
333	data [fill++] = pkt->len >> 8;	374	data [fill++] = pkt->len >> 8;
334	data [fill++] = pkt->len;	375	data [fill++] = pkt->len;
335		376
336	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	377	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
337		378
338	return true;	379	return true;
339	}	380	}
340		381
341	vpn_packet *byte_stream::get ()	382	vpn_packet *byte_stream::get ()
342	{	383	{
		384	unsigned int len;
		385
		386	for (;;)
		387	{
343	int len = (data [0] << 8) \| data [1];	388	len = (data [0] << 8) \| data [1];
344		389
345	if (len > MAXSIZE && fill >= 2)	390	if (len <= MAXSIZE \|\| fill < 2)
346	abort (); // TODO handle this gracefully, connection reset	391	break;
347		392
		393	// TODO: handle this better than skipping, e.g. by reset
		394	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
		395	remove (1);
		396	}
		397
348	if (fill < len + 2)	398	if (fill < len + 2)
349	return 0;	399	return 0;
350		400
351	vpn_packet *pkt = new vpn_packet;	401	vpn_packet *pkt = new vpn_packet;
352		402
353	pkt->len = len;	403	pkt->len = len;
354	memcpy (&((*pkt)[0]), data + 2, len);	404	memcpy (pkt->at (0), data + 2, len);
355	remove (len + 2);	405	remove (len + 2);
356		406
357	return pkt;	407	return pkt;
358	}	408	}
359		409
…		…
376	#define FLAG_RCODE_REFUSED ( 5 << 0)	426	#define FLAG_RCODE_REFUSED ( 5 << 0)
377		427
378	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	428	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
379	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)	429	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
380		430
		431	struct dns_cfg
		432	{
		433	static int next_uid;
		434
		435	u8 id1, id2, id3, id4;
		436
		437	u8 version;
		438	u8 flags;
		439	u8 rrtype;
		440	u8 def_ttl;
		441
		442	u16 client;
		443	u16 uid; // to make request unique
		444
		445	u16 max_size;
		446	u8 seq_cdc;
		447	u8 req_cdc;
		448
		449	u8 rep_cdc;
		450	u8 delay; // time in 0.01s units that the server may delay replying packets
		451	u8 r3, r4;
		452
		453	u8 r5, r6, r7, r8;
		454
		455	void reset (int clientid);
		456	bool valid ();
		457	};
		458
		459	int dns_cfg::next_uid;
		460
		461	void
		462	dns_cfg::reset (int clientid)
		463	{
		464	id1 = 'G';
		465	id2 = 'V';
		466	id3 = 'P';
		467	id4 = 'E';
		468
		469	version = 1;
		470
		471	rrtype = RR_TYPE_TXT;
		472	flags = 0;
		473	def_ttl = 0;
		474	seq_cdc = 26;
		475	req_cdc = 62;
		476	rep_cdc = 0;
		477	max_size = htons (MAX_PKT_SIZE);
		478	client = htons (clientid);
		479	uid = next_uid++;
		480	delay = 0;
		481
		482	r3 = r4 = 0;
		483	r4 = r5 = r6 = r7 = 0;
		484	}
		485
		486	bool
		487	dns_cfg::valid ()
		488	{
		489	// although the protocol itself allows for some configurability,
		490	// only the following encoding/decoding settings are implemented.
		491	return id1 == 'G'
		492	&& id2 == 'V'
		493	&& id3 == 'P'
		494	&& id4 == 'E'
		495	&& seq_cdc == 26
		496	&& req_cdc == 62
		497	&& rep_cdc == 0
		498	&& version == 1;
		499	}
		500
381	struct dns_packet : net_packet	501	struct dns_packet : net_packet
382	{	502	{
383	u16 id;	503	u16 id;
384	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	504	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
385	u16 qdcount, ancount, nscount, arcount;	505	u16 qdcount, ancount, nscount, arcount;
386		506
387	u8 data[MAXSIZE - 6 * 2];	507	u8 data [MAXSIZE - 6 * 2];
388		508
389	int decode_label (char *data, int size, int &offs);	509	int decode_label (char *data, int size, int &offs);
390	};	510	};
391		511
		512	int
392	int dns_packet::decode_label (char *data, int size, int &offs)	513	dns_packet::decode_label (char *data, int size, int &offs)
393	{	514	{
394	char *orig = data;	515	char *orig = data;
395		516
396	memset (data, 0, size);	517	memset (data, 0, size);
397		518
…		…
423	return data - orig;	544	return data - orig;
424	}	545	}
425		546
426	/////////////////////////////////////////////////////////////////////////////	547	/////////////////////////////////////////////////////////////////////////////
427		548
428	struct dns_req	549	static
		550	u16 next_id ()
429	{	551	{
430	dns_packet *pkt;
431	tstamp next;
432	int retry;
433	struct dns_connection *dns;
434	int seqno;
435
436	dns_req (dns_connection *dns);
437	void gen_stream_req (int seqno, byte_stream &stream);
438	};
439
440	static u16 dns_id = 12098; // TODO: should be per-vpn	552	static u16 dns_id = 0; // TODO: should be per-vpn
441		553
442	static u16 next_id ()	554	if (!dns_id)
443	{	555	dns_id = time (0);
		556
444	// the simplest lsfr with periodicity 65535 i could find	557	// the simplest lsfr with periodicity 65535 i could find
445	dns_id = (dns_id << 1)	558	dns_id = (dns_id << 1)
446	\| (((dns_id >> 1)	559	\| (((dns_id >> 1)
447	^ (dns_id >> 2)	560	^ (dns_id >> 2)
448	^ (dns_id >> 4)	561	^ (dns_id >> 4)
449	^ (dns_id >> 15)) & 1);	562	^ (dns_id >> 15)) & 1);
450		563
451	return dns_id;	564	return dns_id;
452	}	565	}
453		566
		567	struct dns_rcv;
		568	struct dns_snd;
		569
		570	struct dns_connection
		571	{
		572	connection *c;
		573	struct vpn *vpn;
		574
		575	dns_cfg cfg;
		576
		577	bool established;
		578
		579	tstamp last_received;
		580	tstamp last_sent;
		581	double min_latency;
		582	double poll_interval, send_interval;
		583
		584	vector<dns_rcv *> rcvpq;
		585
		586	byte_stream rcvdq; int rcvseq; int repseq;
		587	byte_stream snddq; int sndseq;
		588
		589	inline void time_cb (ev::timer &w, int revents); ev::timer tw;
		590	void receive_rep (dns_rcv *r);
		591
		592	dns_connection (connection *c);
		593	~dns_connection ();
		594	};
		595
		596	struct dns_snd
		597	{
		598	dns_packet *pkt;
		599	tstamp timeout, sent;
		600	int retry;
		601	struct dns_connection *dns;
		602	int seqno;
		603	bool stdhdr;
		604
		605	void gen_stream_req (int seqno, byte_stream &stream);
		606	void gen_syn_req ();
		607
		608	dns_snd (dns_connection *dns);
		609	~dns_snd ();
		610	};
		611
454	dns_req::dns_req (dns_connection *dns)	612	dns_snd::dns_snd (dns_connection *dns)
455	: dns (dns)	613	: dns (dns)
456	{	614	{
457	next = 0;	615	timeout = 0;
458	retry = 0;	616	retry = 0;
		617	seqno = 0;
		618	sent = ev_now ();
		619	stdhdr = false;
459		620
460	pkt = new dns_packet;	621	pkt = new dns_packet;
461		622
462	pkt->id = next_id ();	623	pkt->id = next_id ();
463	}	624	}
464		625
		626	dns_snd::~dns_snd ()
		627	{
		628	delete pkt;
		629	}
		630
		631	static void
		632	append_domain (dns_packet &pkt, int &offs, const char *domain)
		633	{
		634	// add tunnel domain
		635	for (;;)
		636	{
		637	const char *end = strchr (domain, '.');
		638
		639	if (!end)
		640	end = domain + strlen (domain);
		641
		642	int len = end - domain;
		643
		644	pkt [offs++] = len;
		645	memcpy (pkt.at (offs), domain, len);
		646	offs += len;
		647
		648	if (!*end)
		649	break;
		650
		651	domain = end + 1;
		652	}
		653	}
		654
		655	void
465	void dns_req::gen_stream_req (int seqno, byte_stream &stream)	656	dns_snd::gen_stream_req (int seqno, byte_stream &stream)
466	{	657	{
		658	stdhdr = true;
467	this->seqno = seqno;	659	this->seqno = seqno;
		660
		661	timeout = ev_now () + INITIAL_TIMEOUT;
468		662
469	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	663	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
470	pkt->qdcount = htons (1);	664	pkt->qdcount = htons (1);
471		665
472	int offs = 6*2;	666	int offs = 6*2;
473	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	667	int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
474	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,	668	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
475	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra	669	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
476		670
477	char enc[256], *encp = enc;	671	char enc[256], *encp = enc;
478	encode_header (enc, THISNODE->id, seqno);	672	encode_header (enc, THISNODE->id, seqno);
…		…
496	encp += lbllen;	690	encp += lbllen;
497		691
498	enclen -= lbllen;	692	enclen -= lbllen;
499	}	693	}
500		694
501	const char *suffix = THISNODE->domain;	695	append_domain (*pkt, offs, dns->c->conf->domain);
502
503	// add tunnel domain
504	for (;;)
505	{
506	const char *end = strchr (suffix, '.');
507
508	if (!end)
509	end = suffix + strlen (suffix);
510
511	int len = end - suffix;
512
513	(*pkt)[offs++] = len;
514	memcpy (&((*pkt)[offs]), suffix, len);
515	offs += len;
516
517	if (!*end)
518	break;
519
520	suffix = end + 1;
521	}
522		696
523	(*pkt)[offs++] = 0;	697	(*pkt)[offs++] = 0;
524	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	698	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		699	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		700
		701	pkt->len = offs;
		702	}
		703
		704	void
		705	dns_snd::gen_syn_req ()
		706	{
		707	timeout = ev_now () + INITIAL_SYN_TIMEOUT;
		708
		709	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		710	pkt->qdcount = htons (1);
		711
		712	int offs = 6 * 2;
		713
		714	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
		715
		716	assert (elen <= MAX_LBL_SIZE);
		717
		718	(*pkt)[offs] = elen;
		719	offs += elen + 1;
		720	append_domain (*pkt, offs, dns->c->conf->domain);
		721
		722	(*pkt)[offs++] = 0;
		723	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
525	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	724	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
526		725
527	pkt->len = offs;	726	pkt->len = offs;
528	}	727	}
529		728
…		…
549	delete pkt;	748	delete pkt;
550	}	749	}
551		750
552	/////////////////////////////////////////////////////////////////////////////	751	/////////////////////////////////////////////////////////////////////////////
553		752
554	struct dns_connection
555	{
556	connection *c;
557	struct vpn *vpn;
558
559	vector<dns_rcv *> rcvpq;
560
561	int rcvseq;
562	int sndseq;
563
564	byte_stream rcvdq;
565	byte_stream snddq;
566
567	void time_cb (time_watcher &w); time_watcher tw;
568	void receive_rep (dns_rcv *r);
569
570	dns_connection (connection *c);
571	~dns_connection ();
572	};
573
574	dns_connection::dns_connection (connection *c)	753	dns_connection::dns_connection (connection *c)
575	: c (c)	754	: c (c)
576	, rcvdq (MAX_BACKLOG * 2)	755	, rcvdq (MAX_BACKLOG * 2)
577	, snddq (MAX_BACKLOG * 2)	756	, snddq (MAX_BACKLOG)
578	, tw (this, &dns_connection::time_cb)
579	{	757	{
		758	tw.set<dns_connection, &dns_connection::time_cb> (this);
		759
580	vpn = c->vpn;	760	vpn = c->vpn;
581		761
		762	established = false;
		763
582	rcvseq = sndseq = 0;	764	rcvseq = repseq = sndseq = 0;
		765
		766	last_sent = last_received = 0;
		767	poll_interval = 0.5; // starting here
		768	send_interval = 0.5; // starting rate
		769	min_latency = INITIAL_TIMEOUT;
583	}	770	}
584		771
585	dns_connection::~dns_connection ()	772	dns_connection::~dns_connection ()
586	{	773	{
587	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	774	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
588	i != rcvpq.end ();	775	i != rcvpq.end ();
589	++i)	776	++i)
590	delete *i;	777	delete *i;
591	}	778	}
592		779
593	struct dns_cfg	780	void
594	{
595	u8 id1, id2, id3;
596	u8 def_ttl;
597	u8 unused1;
598	u16 max_size;
599	u8 flags1, flags2;
600	};
601
602	void dns_connection::receive_rep (dns_rcv *r)	781	dns_connection::receive_rep (dns_rcv *r)
603	{	782	{
		783	if (r->datalen)
		784	{
		785	last_received = ev_now ();
		786	tw ();
		787
		788	poll_interval = send_interval;
		789	}
		790	else
		791	{
		792	poll_interval *= 1.5;
		793
		794	if (poll_interval > MAX_POLL_INTERVAL)
		795	poll_interval = MAX_POLL_INTERVAL;
		796	}
		797
604	rcvpq.push_back (r);	798	rcvpq.push_back (r);
605		799
606	redo:	800	redo:
607		801
608	// find next packet	802	// find next packet
609	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )	803	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
610	if (SEQNO_EQ (rcvseq, (*i)->seqno))	804	if (SEQNO_EQ (rcvseq, (*i)->seqno))
611	{	805	{
		806	//printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
612	// enter the packet into our input stream	807	// enter the packet into our input stream
613	r = *i;	808	r = *i;
614		809
615	// remove the oldest packet, look forward, as it's oldest first	810	// remove the oldest packet, look forward, as it's oldest first
616	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)	811	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
617	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))	812	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
618	{	813	{
		814	//printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
619	delete *j;	815	delete *j;
620	rcvpq.erase (j);	816	rcvpq.erase (j);
621	break;	817	break;
622	}	818	}
623		819
624	rcvseq = (rcvseq + 1) & SEQNO_MASK;	820	rcvseq = (rcvseq + 1) & SEQNO_MASK;
625		821
626	if (!rcvdq.put (r->data, r->datalen))	822	if (!rcvdq.put (r->data, r->datalen))
		823	{
		824	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
627	abort (); // MUST never overflow, can be caused by data corruption, TODO	825	abort (); // MUST never overflow, can be caused by data corruption, TODO
		826	}
628		827
629	while (vpn_packet *pkt = rcvdq.get ())	828	while (vpn_packet *pkt = rcvdq.get ())
630	{	829	{
631	sockinfo si;	830	sockinfo si;
632	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	831	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
633		832
634	vpn->recv_vpn_packet (pkt, si);	833	vpn->recv_vpn_packet (pkt, si);
		834
		835	delete pkt;
635	}	836	}
636		837
637	// check for further packets	838	// check for further packets
638	goto redo;	839	goto redo;
639	}	840	}
640	}	841	}
641		842
642	dns_packet *	843	void
643	vpn::dnsv4_server (dns_packet *pkt)	844	vpn::dnsv4_server (dns_packet &pkt)
644	{	845	{
645	u16 flags = ntohs (pkt->flags);	846	u16 flags = ntohs (pkt.flags);
646		847
647	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
648	int offs = 6 * 2; // skip header	848	int offs = 6 * 2; // skip header
649		849
650	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	850	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
651		851
652	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	852	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
653	&& pkt->qdcount == htons (1))	853	&& pkt.qdcount == htons (1))
654	{	854	{
655	char qname[MAXSIZE];	855	char qname [MAXSIZE];
656	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	856	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
657		857
658	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	858	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
659	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	859	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
660		860
661	pkt->qdcount = htons (1);	861	pkt.qdcount = htons (1);
662	pkt->ancount = 0;	862	pkt.ancount = 0;
663	pkt->nscount = 0; // should be self, as other nameservers reply like this	863	pkt.nscount = 0; // should be self, as other nameservers reply like this
664	pkt->arcount = 0; // a record for self, as other nameservers reply like this	864	pkt.arcount = 0; // a record for self, as other nameservers reply like this
665		865
666	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	866	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
667		867
668	int dlen = strlen (THISNODE->domain);	868	int dlen = strlen (THISNODE->domain);
669		869
670	if (qclass == RR_CLASS_IN	870	if (qclass == RR_CLASS_IN
671	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
672	&& qlen > dlen + 1 + HDRSIZE	871	&& qlen > dlen + 1
673	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	872	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
674	{	873	{
675	// correct class, domain: parse	874	// now generate reply
676	int client, seqno;	875	pkt.ancount = htons (1); // one answer RR
677	decode_header (qname, client, seqno);	876	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
678		877
679	u8 data[MAXSIZE];	878	if ((qtype == RR_TYPE_ANY
680	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));	879	\|\| qtype == RR_TYPE_TXT
681		880	\|\| qtype == RR_TYPE_NULL)
682	if (0 < client && client <= conns.size ())	881	&& qlen > dlen + 1 + HDRSIZE)
683	{	882	{
		883	// correct class, domain: parse
		884	int client, seqno;
		885	decode_header (qname, client, seqno);
		886
		887	u8 data[MAXSIZE];
		888	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
		889
		890	if (0 < client && client <= conns.size ())
		891	{
684	connection *c = conns [client - 1];	892	connection *c = conns [client - 1];
685
686	if (!c->dns)
687	c->dns = new dns_connection (c);
688
689	dns_connection *dns = c->dns;	893	dns_connection *dns = c->dns;
		894	dns_rcv *rcv;
690		895
		896	if (dns)
		897	{
691	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )	898	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
692	if (SEQNO_EQ ((*i)->seqno, seqno))	899	if (SEQNO_EQ ((*i)->seqno, seqno))
		900	{
		901	// already seen that request: simply reply with the cached reply
		902	dns_rcv r = i;
		903
		904	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		905
		906	// refresh header & id, as the retry count could have changed
		907	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		908	r->pkt->id = pkt.id;
		909
		910	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		911
		912	goto duplicate_request;
		913	}
		914
		915	// new packet, queue
		916	rcv = new dns_rcv (seqno, data, datalen);
		917	dns->receive_rep (rcv);
		918	}
		919
693	{	920	{
694	// already seen that request: simply reply with the cached reply	921	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
695	dns_rcv r = i;
696		922
697	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	923	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		924	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		925	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		926	pkt [offs++] = 0; pkt [offs++] = 0;
		927	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
698		928
699	memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len);	929	int rdlen_offs = offs += 2;
700	pkt->id = r->pkt->id;	930
701	goto duplicate_request;	931	if (dns)
		932	{
		933	int dlen = ntohs (dns->cfg.max_size) - offs;
		934
		935	// bind doesn't compress well, so reduce further by one label length
		936	dlen -= qlen;
		937
		938	// only put data into in-order sequence packets, if
		939	// we receive out-of-order packets we generate empty
		940	// replies
		941	//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
		942	if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
		943	{
		944	dns->repseq = seqno;
		945
		946	while (dlen > 1 && !dns->snddq.empty ())
		947	{
		948	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		949
		950	if (txtlen > dns->snddq.size ())
		951	txtlen = dns->snddq.size ();
		952
		953	pkt[offs++] = txtlen;
		954	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
		955	offs += txtlen;
		956	dns->snddq.remove (txtlen);
		957
		958	dlen -= txtlen + 1;
		959	}
		960	}
		961
		962	// avoid completely empty TXT rdata
		963	if (offs == rdlen_offs)
		964	pkt[offs++] = 0;
		965
		966	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
		967	}
		968	else
		969	{
		970	// send RST
		971	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		972	pkt [offs++] = CMD_IP_RST;
		973	}
		974
		975	int rdlen = offs - rdlen_offs;
		976
		977	pkt [rdlen_offs - 2] = rdlen >> 8;
		978	pkt [rdlen_offs - 1] = rdlen;
		979
		980	if (dns)
		981	{
		982	// now update dns_rcv copy
		983	rcv->pkt->len = offs;
		984	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		985	}
702	}	986	}
703		987
704	// new packet, queue	988	duplicate_request: ;
705	dns_rcv *rcv = new dns_rcv (seqno, data, datalen);	989	}
706	dns->receive_rep (rcv);	990	else
707
708	// now generate reply
709	pkt->ancount = htons (1); // one answer RR
710	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	991	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		992	}
		993	else if (qtype == RR_TYPE_A
		994	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		995	{
		996	dns_cfg cfg;
		997	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		998	int client = ntohs (cfg.client);
711		999
712	(*pkt) [offs++] = 0xc0;
713	(pkt) [offs++] = 6 2; // same as in query section	1000	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
714		1001
715	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;	1002	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
716	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;	1003	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
717
718	(pkt) [offs++] = 0; (pkt) [offs++] = 0;	1004	pkt [offs++] = 0; pkt [offs++] = 0;
719	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL	1005	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		1006	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
720		1007
721	int dlen = MAX_PKT_SIZE - offs - 2;	1008	slog (L_INFO, _("DNS: client %d connects"), client);
722		1009
723	// bind doesn't compress well, so reduce further by one label length	1010	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
724	dlen -= qlen;	1011	pkt [offs++] = CMD_IP_REJ;
725		1012
726	int rdlen_offs = offs += 2;	1013	if (0 < client && client <= conns.size ())
727
728	while (dlen > 1 && !dns->snddq.empty ())
729	{	1014	{
730	int txtlen = dlen <= 255 ? dlen - 1 : 255;	1015	connection *c = conns [client - 1];
731		1016
732	if (txtlen > dns->snddq.size ())	1017	if (cfg.valid ())
733	txtlen = dns->snddq.size ();	1018	{
		1019	pkt [offs - 1] = CMD_IP_SYN;
734		1020
735	(*pkt)[offs++] = txtlen;	1021	delete c->dns;
736	memcpy (pkt->at (offs), dns->snddq.begin (), txtlen);	1022	c->dns = new dns_connection (c);
737	offs += txtlen;	1023	c->dns->cfg = cfg;
738	dns->snddq.remove (txtlen);	1024	}
739
740	dlen -= txtlen + 1;
741	}	1025	}
742
743	// avoid empty TXT rdata
744	if (offs == rdlen_offs)
745	(*pkt)[offs++] = 0;
746
747	int rdlen = offs - rdlen_offs;
748
749	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
750	(*pkt) [rdlen_offs - 1] = rdlen;
751
752	// now update dns_rcv copy
753	rcv->pkt->len = offs;
754	memcpy (rcv->pkt->at (0), pkt->at (0), offs);
755
756	duplicate_request: ;
757	}	1026	}
758	else
759	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
760	}	1027	}
761		1028
762	pkt->len = offs;	1029	pkt.len = offs;
763	}	1030	}
764
765	return pkt;
766	}	1031	}
767		1032
768	void	1033	void
769	vpn::dnsv4_client (dns_packet *pkt)	1034	vpn::dnsv4_client (dns_packet &pkt)
770	{	1035	{
771	u16 flags = ntohs (pkt->flags);	1036	u16 flags = ntohs (pkt.flags);
772	int offs = 6 * 2; // skip header	1037	int offs = 6 * 2; // skip header
773		1038
774	pkt->qdcount = ntohs (pkt->qdcount);	1039	pkt.qdcount = ntohs (pkt.qdcount);
775	pkt->ancount = ntohs (pkt->ancount);	1040	pkt.ancount = ntohs (pkt.ancount);
776		1041
777	// go through our request list and find the corresponding request	1042	// go through our request list and find the corresponding request
778	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	1043	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
779	i != dns_sndpq.end ();	1044	i != dns_sndpq.end ();
780	++i)	1045	++i)
781	if ((*i)->pkt->id == pkt->id)	1046	if ((*i)->pkt->id == pkt.id)
782	{	1047	{
783	dns_connection dns = (i)->dns;	1048	dns_connection dns = (i)->dns;
		1049	connection *c = dns->c;
784	int seqno = (*i)->seqno;	1050	int seqno = (*i)->seqno;
785	u8 data[MAXSIZE], *datap = data;	1051	u8 data[MAXSIZE], *datap = data;
		1052	//printf ("rcv pkt %x\n", seqno);//D
		1053
		1054	if ((*i)->retry)
		1055	{
		1056	dns->send_interval *= 1.01;
		1057	if (dns->send_interval > MAX_SEND_INTERVAL)
		1058	dns->send_interval = MAX_SEND_INTERVAL;
		1059	}
		1060	else
		1061	{
		1062	#if 0
		1063	dns->send_interval *= 0.999;
		1064	#endif
		1065	// the latency surely puts an upper bound on
		1066	// the minimum send interval
		1067	double latency = ev_now () - (*i)->sent;
		1068
		1069	if (latency < dns->min_latency)
		1070	dns->min_latency = latency;
		1071
		1072	if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
		1073	dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
		1074
		1075	if (dns->send_interval < conf.dns_send_interval)
		1076	dns->send_interval = conf.dns_send_interval;
		1077	}
786		1078
787	delete *i;	1079	delete *i;
788	dns_sndpq.erase (i);	1080	dns_sndpq.erase (i);
789		1081
790	if (flags & FLAG_RESPONSE && !(flags & (FLAG_OP_MASK \| FLAG_TC)))	1082	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
791	{	1083	{
792	char qname[MAXSIZE];	1084	char qname[MAXSIZE];
793		1085
794	while (pkt->qdcount-- && offs < MAXSIZE - 4)	1086	while (pkt.qdcount-- && offs < MAXSIZE - 4)
795	{	1087	{
796	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1088	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
797	offs += 4; // skip qtype, qclass	1089	offs += 4; // skip qtype, qclass
798	}	1090	}
799		1091
800	while (pkt->ancount-- && offs < MAXSIZE - 10 && datap)	1092	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
801	{	1093	{
802	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1094	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
803		1095
804	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1096	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
805	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1097	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
806	u32 ttl = (*pkt) [offs++] << 24;	1098	u32 ttl = pkt [offs++] << 24;
807	ttl \|= (*pkt) [offs++] << 16;	1099	ttl \|= pkt [offs++] << 16;
808	ttl \|= (*pkt) [offs++] << 8;	1100	ttl \|= pkt [offs++] << 8;
809	ttl \|= (*pkt) [offs++];	1101	ttl \|= pkt [offs++];
810
811	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1102	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
812		1103
813	if (rdlen <= MAXSIZE - offs)	1104	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
814	{	1105	{
815	// decode bytes, finally	1106	if (rdlen <= MAXSIZE - offs)
816
817	while (rdlen)
818	{	1107	{
		1108	// decode bytes, finally
		1109
		1110	while (rdlen)
		1111	{
819	int txtlen = (*pkt) [offs++];	1112	int txtlen = pkt [offs++];
820		1113
821	assert (txtlen + offs < MAXSIZE - 1);	1114	assert (txtlen + offs < MAXSIZE - 1);
822		1115
823	memcpy (datap, pkt->at (offs), txtlen);	1116	memcpy (datap, pkt.at (offs), txtlen);
824	datap += txtlen; offs += txtlen;	1117	datap += txtlen; offs += txtlen;
825		1118
826	rdlen -= txtlen + 1;	1119	rdlen -= txtlen + 1;
		1120	}
827	}	1121	}
828	}	1122	}
		1123	else if (qtype == RR_TYPE_A)
		1124	{
		1125	u8 ip [4];
		1126
		1127	ip [0] = pkt [offs++];
		1128	ip [1] = pkt [offs++];
		1129	ip [2] = pkt [offs++];
		1130	ip [3] = pkt [offs++];
		1131
		1132	if (ip [0] == CMD_IP_1
		1133	&& ip [1] == CMD_IP_2
		1134	&& ip [2] == CMD_IP_3)
		1135	{
		1136	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
		1137
		1138	if (ip [3] == CMD_IP_RST)
		1139	{
		1140	slog (L_DEBUG, _("DNS: got tunnel RST request"));
		1141
		1142	delete dns; c->dns = 0;
		1143
		1144	return;
		1145	}
		1146	else if (ip [3] == CMD_IP_SYN)
		1147	{
		1148	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
		1149	dns->established = true;
		1150	}
		1151	else if (ip [3] == CMD_IP_REJ)
		1152	{
		1153	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1154	abort ();
		1155	}
		1156	else
		1157	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
		1158	}
		1159	else
		1160	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
		1161	ip [0], ip [1], ip [2], ip [3]);
		1162
		1163	return;
		1164	}
829		1165
830	int client, rseqno;	1166	int client, rseqno;
831	decode_header (qname, client, rseqno);	1167	decode_header (qname, client, rseqno);
832		1168
833	if (client != THISNODE->id)	1169	if (client != THISNODE->id)
834	{	1170	{
835	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));	1171	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
836	datap = 0;	1172	datap = 0;
837	}	1173	}
838	else if (rseqno != seqno)	1174	else if (rseqno != seqno)
839	{	1175	{
840	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));	1176	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
841	datap = 0;	1177	datap = 0;
842	}	1178	}
843	}	1179	}
844	}	1180	}
845		1181
…		…
847	if (datap)	1183	if (datap)
848	dns->receive_rep (new dns_rcv (seqno, data, datap - data));	1184	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
849		1185
850	break;	1186	break;
851	}	1187	}
852
853	delete pkt;
854	}	1188	}
855		1189
856	void	1190	void
857	vpn::dnsv4_ev (io_watcher &w, short revents)	1191	vpn::dnsv4_ev (ev::io &w, int revents)
858	{	1192	{
859	if (revents & EVENT_READ)	1193	if (revents & EV_READ)
860	{	1194	{
861	dns_packet *pkt = new dns_packet;	1195	dns_packet *pkt = new dns_packet;
862	struct sockaddr_in sa;	1196	struct sockaddr_in sa;
863	socklen_t sa_len = sizeof (sa);	1197	socklen_t sa_len = sizeof (sa);
864		1198
865	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1199	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
866		1200
867	if (pkt->len > 0)	1201	if (pkt->len > 0)
868	{	1202	{
869	if (pkt->flags & htons (FLAG_TC))	1203	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1204	dnsv4_client (*pkt);
		1205	else
870	{	1206	{
871	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));	1207	dnsv4_server (*pkt);
872	//TODO connection reset	1208	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
873	}	1209	}
874		1210
875	if (THISNODE->dns_port)	1211	delete pkt;
876	{
877	pkt = dnsv4_server (pkt);
878	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);
879	}
880	else
881	dnsv4_client (pkt);
882	}	1212	}
883	}	1213	}
884	}	1214	}
885		1215
886	bool	1216	bool
887	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1217	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
888	{	1218	{
		1219	int client = ntohl (si.host);
		1220
		1221	assert (0 < client && client <= conns.size ());
		1222
		1223	connection *c = conns [client - 1];
		1224
889	if (!dns)	1225	if (!c->dns)
890	dns = new dns_connection (this);	1226	c->dns = new dns_connection (c);
891		1227
892	if (!dns->snddq.put (pkt))	1228	if (c->dns->snddq.put (pkt))
893	return false;	1229	c->dns->tw ();
894		1230
895	// start timer if neccessary	1231	// always return true even if the buffer overflows
896	if (!THISNODE->dns_port && !dns->tw.active)
897	dns->tw.trigger ();
898
899	return true;	1232	return true;
900	}	1233	}
901		1234
902	void	1235	void
903	dns_connection::time_cb (time_watcher &w)	1236	connection::dnsv4_reset_connection ()
904	{	1237	{
		1238	//delete dns; dns = 0; //TODO
		1239	}
		1240
		1241	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1242
		1243	void
		1244	dns_connection::time_cb (ev::timer &w, int revents)
		1245	{
		1246	// servers have to be polled
		1247	if (THISNODE->dns_port)
		1248	return;
		1249
905	// check for timeouts and (re)transmit	1250	// check for timeouts and (re)transmit
906	tstamp next = NOW + 60;	1251	tstamp next = ev::now () + poll_interval;
907	dns_req *send = 0;	1252	dns_snd *send = 0;
908		1253
909	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1254	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
910	i != vpn->dns_sndpq.end ();	1255	i != vpn->dns_sndpq.end ();
911	++i)	1256	++i)
912	{	1257	{
913	dns_req r = i;	1258	dns_snd r = i;
914		1259
915	if (r->next <= NOW)	1260	if (r->timeout <= ev_now ())
916	{	1261	{
917	if (!send)	1262	if (!send)
918	{	1263	{
919	send = r;	1264	send = r;
920		1265
921	if (r->retry)//D
922	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
923	r->retry++;	1266	r->retry++;
924	r->next = NOW + r->retry;	1267	r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
		1268	//printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
		1269
		1270	// the following code changes the query section a bit, forcing
		1271	// the forwarder to generate a new request
		1272	if (r->stdhdr)
		1273	encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
925	}	1274	}
926	}	1275	}
927		1276	else
928	if (r->next < next)	1277	NEXT (r->timeout);
929	next = r->next;
930	}	1278	}
931		1279
932	if (!send	1280	if (!send)
933	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)
934	{	1281	{
		1282	// generate a new packet, if wise
		1283
		1284	if (!established)
		1285	{
		1286	if (vpn->dns_sndpq.empty ())
		1287	{
935	send = new dns_req (this);	1288	send = new dns_snd (this);
		1289
		1290	cfg.reset (THISNODE->id);
		1291	send->gen_syn_req ();
		1292	}
		1293	}
		1294	else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
		1295	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1296	{
		1297	if (last_sent + send_interval <= ev_now ())
		1298	{
		1299	//printf ("sending data request etc.\n"); //D
		1300	if (!snddq.empty () \|\| last_received + 1. > ev_now ())
		1301	{
		1302	poll_interval = send_interval;
		1303	NEXT (ev_now () + send_interval);
		1304	}
		1305
		1306	send = new dns_snd (this);
936	send->gen_stream_req (sndseq, snddq);	1307	send->gen_stream_req (sndseq, snddq);
		1308	send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
		1309	//printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
		1310
		1311	sndseq = (sndseq + 1) & SEQNO_MASK;
		1312	}
		1313	else
		1314	NEXT (last_sent + send_interval);
		1315	}
		1316
		1317	if (send)
937	vpn->dns_sndpq.push_back (send);	1318	vpn->dns_sndpq.push_back (send);
938
939	sndseq = (sndseq + 1) & SEQNO_MASK;
940	}	1319	}
941
942	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
943		1320
944	if (send)	1321	if (send)
945	{	1322	{
946	dns_packet *pkt = send->pkt;	1323	last_sent = ev_now ();
947		1324	sendto (vpn->dnsv4_fd,
948	next = min_next;	1325	send->pkt->at (0), send->pkt->len, 0,
949
950	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0,
951	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1326	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
952	}	1327	}
953	else if (next < min_next)
954	next = min_next;
955		1328
956	w.start (next);	1329	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1330	poll_interval, send_interval, next - ev_now (),
		1331	vpn->dns_sndpq.size (), snddq.size (),
		1332	rcvpq.size ());
		1333
		1334	// TODO: no idea when this happens, but when next < ev_now (), we have a problem
		1335	// doesn't seem to happen anymore
		1336	if (next < ev_now () + 0.001)
		1337	next = ev_now () + 0.1;
		1338
		1339	w.start (next - ev_now ());
957	}	1340	}
958		1341
959	#endif	1342	#endif
960		1343

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs. Revision 1.49 by root, Tue Feb 8 23:11:36 2011 UTC

Diff Legend

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs.
Revision 1.49 by root, Tue Feb 8 23:11:36 2011 UTC